in britain in 1997. it caught on here in the u.s. 5,000 schools here are expected to participate along with students from 40 countries around the world. in all, more than 3 million kids will walk. >> this is your first year doing the walk to school day? >> yes. >> reporter: what do you think? >> it's great. >> reporter: how do you like it? >> because i like walking. >> reporter: the idea to talk with students about the importance of physical activity, raise their concern for the environment and focus on the need for safer routes for walking. >> it represents what can happen in a split second. two teenagers hit not far froo here. >> the fire chief put his walking shoes on along with councilmembers and local officials joining students, staff and parents. >> i think the kids absolutely love it. if it were up to the kids, they would do this every day. >> reporter: to end the morning, a performance for us, a song about pedestrian safety as they geared up for this year's walk to school day. this isn't the end of it. many of these kids say they plan to walk home as well at the end of the day.